/sys/src/libc/9syscall/mkfile has a rather odd looking special case for the
seek system call... it looks like if seek fails (returns -1) that the first
two arguments (fd and offset) are overwritten with -1. What's going on
here? The manual page doesn't hint at anything...
Thanks.
--nwf;
On Mon, Oct 20, 2008 at 09:19:50AM +0100, C H Forsyth wrote:
seek is unusual because it returns a 64-bit value
Forgive my ignorance, but I don't see how the code in question relates to
returning a 64-bit value?
--nwf;
pgpZuSgZQbGYG.pgp
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The seek system call is here
/sys/src/9/port/sysfile.c:855
The arg variable here is a pointer to the users stack making
the system call. most return values are 32 bit and are passed
back through syscall()
/sys/src/9/pc/trap.c:660
but seek is different, it overwrites 64 bits
On Mon, Oct 20, 2008 at 10:11:22PM +0100, Charles Forsyth wrote:
Forgive my ignorance, but I don't see how the code in question relates to
returning a 64-bit value?
MOVL a+0(FP),CX
MOVL AX,0(CX)
MOVL
Forgive my ignorance, but I don't see how the code in question relates to
returning a 64-bit value?
MOVL a+0(FP),CX
MOVL AX,0(CX)
MOVL AX,4(CX)
that's how a 64-bit value is returned on 32-bit machines:
